The present invention relates to a staircase and a staircase repair device adapted to be used for both residential and commercial buildings and, more particularly, to a staircase including specially constructed stair tread members for use with standard stringers, and a staircase repair device or kit which can refurbish an existing staircase in need of repair without modification of the original staircase. Methods are also provided for fabrication.
A number of prior art devices exist which relate to the construction of a staircase, or the repair or refurbishing of a staircase. Particularly for conventional outside stairs and emergency stairs in both residential and commercial applications, such stairs are often constructed of materials which do not withstand heavy traffic or harsh environmental conditions. Because of safety concerns, stairs should always be kept in a high state of maintenance. However, the cost to repair damaged staircases can be quite prohibitive, even for minor flaws. For example, stairs formed of concrete which have chips or other surface defects are not only dangerous, but are also unsightly. Concrete repair is usually a very temporary measure and, particularly in high traffic areas, the concrete repair is never as wear-resistant as the original concrete. For wooden stairs, the wood has a tendency to warp or deform along heavy traffic areas. Even if constructed of treated lumber, the wood becomes unsightly over time.
There are a number of examples of prior art devices which have attempted to overcome one or more of the following problems. These devices can be in the form of either a repair unit, or a complete staircase construction.
U.S. Pat. No. 5,357,724 discloses a stair tread in which rubber sheet material is placed around a metal core section, and then heated to melt the sheets together. Once heated, the core section is encapsulated within the rubber. The stair tread has anti-slip serrations formed on its upper surface. A front face or overhanging front lip forms the front edge of the stair tread, and a vertically extending rear flange forms the rear face or edge of the stair tread. The upper edge of the rear face has a groove to accept the lower edge of a riser board, while the upper edge of the riser board is inserted into a corresponding groove formed in the lower edge of the front face of the next higher stair tread.
U.S. Pat. No. 5,799,448 discloses an adjustable closed riser metal staircase system. The system includes a plurality of stair treads which may be assembled into staircases having different rise heights. The stair treads include a vertical riser portion and a horizontal walking surface, preferably made of a slip-resistant material such as Mebac(trademark), a coating of thermally sprayed steel encapsulating a dispersion of grit materials, normally aluminum oxide. The nose piece portion of the stair tread is formed at the front of the stair by bending the forward edge of the steel plate downward. When assembled, the upper end of the riser portion is inserted within a channel created by the bent nosepiece of the next higher stair tread assembly.
U.S. Pat. No. 4,783,939 discloses a composite covering for improving worn out treadways of steps. This covering includes a stair tread section which is placed over the existing stair tread, and an integral vertical flange which overhangs the front lip of the stair tread section. The covering is constructed of a scuff-resistant plastic. The underside of the stair tread section includes an insert of pressboard, and a binder which helps raise the elevation of worn out sections or indentations, and also serves to bind the layers of the composite covering.
U.S. Pat. No. 5,660,009 discloses a metal stairway construction in which stair steps are supported between a pair of trimmed sheet metal stringer panels on each side of the stairway. Each step of the stairway is formed of metal treads and risers cut to appropriate lengths from conventional joice members provided on site. The metal treads and risers are attached at opposite ends thereof to respective stringer panels by way of standard angle brackets. Threaded self-drilling fasteners attach each angle bracket to a corresponding stringer panel and to an associated metal tread or metal riser. Wooden treads and risers are attached over the corresponding metal treads and risers by standard self-drilling screws.
While the foregoing references may be adequate for their intended purposes, there are certain advantages with the present invention which are not found in these references. One advantage is that the staircase repair device of this invention can be used with any type of existing staircase, whether it be concrete, wood, or metal. Another advantage is that this staircase repair device can be used to repair a staircase without preparation or modification of the original staircase wear surfaces. Yet another advantage not overcome by the prior art is the use of a staircase repair device which has high strength and weathering capabilities, yet does not detract from the general aesthetic appearance of the staircase. The same advantages discussed above also apply to the staircase of this invention. Additionally, the staircase of this invention is simple in design, and can be used for stairways in a wide array of residential and commercial buildings.
In accordance with this invention, a staircase and a staircase repair device or kit are provided. The staircase repair device or kit forms a first embodiment and is comprised of two major components, namely, a stair tread repair member and a riser repair member. Both of these members are constructed of metal, preferably raw steel, bent to desired shapes. The stair tread repair member includes a front flange and an inward protruding lip. Holes may be drilled in the wearing surface of the stair tread repair member in order to accept fasteners which help to secure the stair tread repair member to an existing stair tread. The riser repair member includes an outward protruding flange. Holes may also be drilled in the riser repair member to accept fasteners for attachment of the riser repair member to an existing staircase riser. Both the stair tread and riser repair members are coated with a synthetic material which protects the metal from corrosion and other environmental hazards. The coating is preferably in the form of a polyurea or polyurethane which is sprayed in liquid form to encapsulate the members therein. The upper wearing surface of the stair tread repair member also has a slip-free surface. This slip-free surface is formed by particles which are spread or sprinkled over the first sprayed coating of synthetic material. These particles are spread on the first coating while it is wet which allows the particles to become embedded in the first coating. Then, a second coating of synthetic material is sprayed over the embedded particles to seal the particles between the first and second coatings. The particles may be materials such as coal dust, aluminum oxide, walnut shells, and other known granular-type material which is used to create slip-free surfaces. It shall be understood that the stair tread repair member serves as a subcombination which may be used to repair the stair treads of an existing staircase.
In a second embodiment, the invention is a staircase which includes a plurality of stair tread members which span between a pair of spaced stringers. The stair tread member is similar to the stair tread repair member of the first embodiment in that it is also constructed of metal bent to a desired shape encapsulated within a first coating of synthetic material, and having a slip-free surface made of a particulate material sandwiched between the first coating and a second applied coating. The stair tread member further includes a pair of opposed side flanges disposed on opposite ends of the stair tread member, and opposing front and rear flanges. The stair tread member spans between a pair of common stringers used in construction of staircases. The stair tread member may be mounted to the facing inner surfaces of the stringers, or may be mounted over the outer surfaces of the stringers. Optionally, an L bracket or other similar supporting hardware may be used to secure the stair tread member to the inner surfaces of the stringers.
The second embodiment may be used in conjunction with either metal or wood stringers. Holes are drilled in the side flanges for receiving fasteners which secure the stair tread member to the stringers. If desired, a riser member could also be used with the invention of the second embodiment. More specifically, a riser similar to the riser repair member of the first embodiment could be used in the second embodiment. The riser in the second embodiment could simply be rectangular in shape and coated in the same way as the other components.
Methods of fabricating a stair tread repair member and of fabricating a stair tread member in a new staircase are also provided. Both methods involve the provision of a flat sheet of metal cut to a desired size. The metal sheet is sanded to roughen its surfaces in preparation for coating with a synthetic material. A primer may be applied to further prepare the metal sheet for coating. The metal sheet is bent by a metal brake machine to the desired shape. In fabrication of the stair tread repair member, the sheet is bent to form the front flange and inward protruding lip. For the stair tread member of a new staircase, the sheet is bent to include front and rear flanges, and the opposed side flanges. In order to bend the sheet of metal used in the stair tread member, corner sections are removed. After the sheet has been bent, the joints formed at the corners of the stair tread members may be welded together. Prior to or after bending, screw holes are punched or drilled in the metal sheets enabling fasteners to be received therethrough.
Once the stair tread repair member and the stair tread member have been bent to the desired shapes, they may be sprayed with a synthetic coating, preferably the polyurea or polyurethane. This coating can be applied to all exposed surfaces. The coating of the members helps to ensure that all surfaces are protected from corrosion and other environmental hazards. The upper wearing surfaces of the members are then sprinkled with a dispersed layer of particles. This preferably occurs when the first applied coating is still wet which enables the particles to become embedded within the first coating. A second coating is then applied over the dispersed layer of particles to encapsulate the particles between the first and second coatings. A slip-free surface is therefore formed by the second coating covering the particles. In addition to providing weather-resistant surfaces, the coatings of polyurea or polyurethane also help to dampen noise normally associated with metal stair treads, and help to keep the wearing surfaces scuff-free. Additionally, the applied coating may be mixed with a desired color which enables the components to match or complement existing colors on the building. For the staircase embodiment, the stair tread members may include diagonal stress lines pressed on the upper wearing surfaces. This pre-stressing of the upper wearing surfaces adds strength to resist any buckling or wobbling of the upper wearing surfaces.
The apparatuses and methods of this invention provide a staircase repair device and a staircase which are extremely durable, simple in construction, aesthetically pleasing, have integral slip-free surfaces, and resist scuffing. Furthermore, these devices are simple to install and are universal in their ability to be used for all types of buildings.
Additional advantages of this invention will become apparent from the description which follows, taken in conjunction with the accompanying drawings.